1. Field of the Invention
The present invention generally relates to a part positioner for fixing parts to a mounting surface and, in particular, to a part positioner suitable for clamping and fixing parts to a mounting surface, such as a guide bar of a chain saw. The present invention also relates to a part pressing member constituting the part positioner, and the parts to be clamped and secured in position.
2. Background of the Invention
U.S. Pat. No. 6,256,890 discloses a rectangular-plate-like guide bar as a component of a chain saw, as an example of parts clamped and fixed to a mounting surface. This guide bar has guide grooves for guiding a saw chain on its outer periphery and is fixed to the guide-bar mounting surface of a chain saw main body as the aforementioned mounting surface. A stud bolt constituting a clamping fixture protrudes from the mounting surface to be inserted into a long mounting hole that is formed in the guide bar so as to extend in the length direction, i.e., a direction along which the mounting position of the guide bar to the chain saw main body is adjusted. With the stud bolt inserted into the long mounting hole of the guide bar and covered with a side cover that has an insertion hole for the stud bolt and serves as a pressing member, a nut (the nut and stud bolt constitute the clamping fixture) is tightened onto a tip end of the stud bolt, thereby clamping the guide bar to the guide-bar mounting surface with the aid of the side cover.
The guide bar should be securely and immovably fixed with respect to the chain saw main body. However, when the chain saw is being used, heavy load is successively applied to the leading end of the guide bar, and there is a fear that the mounted guide bar rattles. The guide bar is especially more likely to rattle in a chain saw having only one pair of a stud bolt and a nut as the clamping fixture.
In order to securely fix the guide bar to the chain saw main body, it is also required not to sacrifice the attachability/removability of the guide bar. That is, if fixed with plural clamping fixtures, the guide bar is of course securely fixed. However, if this means that replacement of the guide bar is complicated, such replacement is burdensome for a user.